Eli5: Why do domestic fire alarms take a rectangular battery instead of AA/AAA?
In: 12
They need the higher voltage
A rectangular 9V battery is just 6 AAAA batteries in a box
If you want to get 9V from AA or AAA batteries then you still need 6 but now your battery compartment is longer and wider taking up wayyy more volume in the smoke detector making it a lot bigger
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